Laser action and photoisomeric transformations in polymethine dyes

A study was made of stimulated emission from a series of polymethine dyes, differing in respect of the radical incorporated in the polymethine chain, and of the effect of photoisomeric transformations in excited states on the emission. The absorption spectra of the photoisomers and their lifetimes in the nonequilibrium state were determined. An energy level scheme was deduced and the channeb of radiative and nonradiative transitions in this series of dyes were identified.